Closure having an adjustable volume sealant chamber

ABSTRACT

A closure is provided including a casing part having at least one opening configured to receive an elongate object within the casing part. A sealing chamber defined by the casing part is positioned adjacent the opening so as to receive the elongate object in the sealing chamber and a sealant material is positioned in the sealing chamber. A relatively displaceable wall part of the casing part in provided in various embodiments which communicatively contacts the sealant material and is coupled to another part of the casing part by a flexible hinge part so as to allow movement of the relatively displaceable wall part relative to the other part of the casing. A compression means may be provided for applying a compressive force to the sealant material through the relatively displaceable wall part. In further embodiments a displaceable plunger is provided defining a wall of the sealing chamber and an externally operable shaft threadably engages the plunger so as to displace the plunger to adjust a volume of the sealant chamber.

FIELDS OF THE INVENTION

The present invention relates generally to a closure, and particularlyto a closure for enclosing one or more elongate objects.

The present invention finds particular utility as a closure forprotecting junctions between elongate objects such as pipes or cables.The term “cable” will be understood hereinafter to include bothconductive cables and bundles of optical fibres. When it is necessary tomake connections between elongate objects such as pipes or cables thejunction or splice where such objects are joined end-to-end isnecessarily less strong and less resistive to environmental agentsliable to cause deterioration over time than the cable itself.

BACKGROUND OF THE INVENTION

In the production of, for example, cable systems such astelecommunication or power transmission systems, it is frequentlynecessary to make splices either to join cables end-to-end or to make abranch. The cables and the splices may be located underground, inconduits or in other environments, inside or outside buildings, but inany event are always at risk to the ingress of environmental agents suchas moisture and humidity or dust. Underground installations are alsosubject to pressure, and in particular hydrostatic pressure, whilstabove-ground installations suffer from diurnal thermal dilatations. Inorder to provide environmental seals for splices in cables or otherelongate objects various protective measures are known. Systemsutilising an enclosing casing with a gel or other suitable sealingmaterial enclosed within it have been found to be particularly valuable.One advantage of using closures containing a gel or other such sealingmaterial lies in the fact that they can be installed at roomtemperature, and by utilising compression means the gel can bemaintained in contact with all the interior surfaces of a closure aswell as the exterior surfaces of the cable or other elongate object thesplice in which is to be protected. The force applied by the compressionmeans must be sufficiently great to overcome any forces which may beexerted by the environmental agents, such as the hydrostatic head inunderground installations. The requirement for a compressive force on asealing material has been recognised for some years and is described invarious prior art documents. In particular, U.S. Pat. No. 4,600,261(Raychem) describes an apparatus and method for protection of electricalcontacts in which the apparatus includes a gel, first means to containthe gel, second means to retain the gel within the first means, and aforce means which acts on the first means so that the gel is maintainedin compressive contact with the electrical contacts and substantiallyencapsulates the conductive portion of them.

In that document the means for applying the force comprised an externalclip or spring by which two halves of a closure casing were heldtogether and pressed into contact with one another by the spring.Although effective this system has the disadvantage that the componentsmust be made to accommodate a particular size (or relatively narrow sizerange) of elongate objects over which the spring can exert anappropriate force.

In order to ensure the sealing effect cable closures incorporatingrelatively displaceable end walls displaceable by screw-threaded meanswere devised, as described in WO 95/15600 (Raychem). A spring interposedbetween a nut and a displaceable end wall acting effectively as a pistonallowed compression to be applied to a sealing material encapsulatedwithin the sealing closure. It was also appreciated that thedisplacement direction need not be parallel to the length of theelongate objects enclosed within the casing, but could be transversethis direction, and the above prior art document also describes theprovision of piston-like members acting perpendicularly to the length ofan enclosed cable whereby to place a gel under compression.

Although all of these arrangements act well to provide a secure sealthey nevertheless offer only a secure seal over a relatively limitedrange of cable diameters. In order to be able to provide a secure sealover a relatively large range of diameters of elongate objects such ascables a relatively large range of movement must be available in orderto change the volume of the containment closure over a wide range.

SUMMARY OF THE INVENTION

The present invention seeks to provide a closure for elongate objectswhich is capable of accommodating such objects over a relatively widerange of dimensions, preferably up to a 3:1 ratio of diameters, whilstnevertheless offering a secure seal against environmental agencies.

According to one aspect of the present invention a closure casingcomprises two casing parts, means for holding the two casing partstogether in juxtaposed relationship, and having means for sealingbetween an elongate article penetrating the casing and the casingitself, the casing parts having respective cavities together forming asealant chamber for receiving sealant material and through which theelongate article passes in penetrating the closure casing, the volume ofthe sealant chamber being adjustable whereby to apply a compressiveforce to sealant material therein, the adjustment being effected bydisplacement of at least one element located within the said sealantchamber, the said element being displaceable within the chamber byselectively operable position—adjustment means of the casing whereby todetermine the effective volume of the sealant chamber.

According to a second, more general aspect of the present inventionthere is provided a closure casing having means for sealing a spacebetween an elongate article penetrating the casing and the casingitself, the casing comprising two opposite casing parts having means forholding them together in juxtaposed relationship and each havingrespective cavities together forming a sealant chamber for receivingsealant material and through which the elongate article passes inpenetrating the closure casing, and means for applying a compressiveforce to the sealant material transversely of the length of the elongatearticle whereby to urge it into intimate contact with the said elongatearticle to seal thereto, in which the said means for applying acompressive force comprise selectively operable adjustment means fordetermining displacement of a movable member the position of whichdetermines the effective volume of the said sealant chamber.

In one embodiment of the present invention the said displaceable elementcomprises a plunger guided for movement within the said sealant chamberin a direction substantially transverse the length of the said elongatearticle. Preferably there are two relatively displaceable plungersinterconnected and guided for substantially rectilinear movement withinthe said sealant chamber.

The said two plungers may be interconnected by screw threaded adjustmentmeans.

Compression on the sealant may be maintained after adjustment, despitechanges in volume due to thermal and other effects if there are providedenergy storage means between the adjustable position-determining meansand the said at least one displacement element. Such energy storagemeans may comprise a spring, preferably a compression coil spring.

In a preferred embodiment of the invention the screw threaded adjustmentmeans comprise a threaded shaft having operating means at one endthereof by which the shaft is turnable, and a cooperating threaded holein one of the said two plungers, the spring acting between the other ofthe two plungers and the said operating means.

In another aspect the present invention comprises a closure comprising aclosure casing having openings for the passage of elongate objects andsealing means including a sealing material enclosed within at least partof the closure casing, in which the sealing means includes a relativelydisplaceable wall part of the closure joined to the remaining part ofthe closure by a flexible hinge part, and adjustableposition-determining means for determining the relative position of thesaid relatively displaceable part of the closure and the remaining partthereof whereby to regulate the effective volume of the said part of theclosure and thus the pressure on a material contained therein.

Preferably the said flexible hinge part is of corrugated or bellowsconfiguration and extends at least partly around the said relativelydisplaceable wall part. Alternatively the flexible hinge part maycomprise or include ligament hinges between appropriately shaped hingedwall parts. As used in this specification the term “ligament hinge” willbe understood to refer to a hinge formed integrally in a body ofmaterial such as polypropylene and defined by a line of reducedthickness at which molecular orientation under stress takes place duringpreliminary flexing.

The said flexible hinge part is, however, preferably formed as a rollseal. The roll seal preferably comprises a flexible wall portion aroundthe periphery of the said relatively displaceable wall part, having asingle U-shape cross section. This U-shape cross section may be convextowards the interior or the exterior of the casing although, for reasonswhich will be explained in more detail below, it is preferred that theroll seal is convex towards the interior of the casing.

In order to obtain the maximum range of variation in the dimensions ofthe elongate objects which can be sealingly accommodated within theclosure it is preferred that the said relatively displaceable wall partof the closure is displaceable transversely of the length direction ofthe said elongate objects.

Various different means for determining the position of the relativelydisplaceable wall part may be adopted. Preferably, however, theadjustable position-determining means comprise co-operatingscrew-threaded components acting to apply a force between the saidrelatively displaceable wall part of the closure and the remaining partthereof. Alternatively, lever mechanisms, especially toggle mechanismsmay be provided for this purpose.

In embodiments in which the adjustable position-determining means arescrew-threaded components, there may be further provided energy storagemeans between the said adjustable position-determining means and thesaid relatively displaceable wall part of the closure. Conveniently suchenergy storage means comprise a spring which, in the preferredembodiment is a compression spring, preferably a coil spring.

In one embodiment of the invention the co-operating screw-threadedcomponents comprise a threaded shaft and a nut, one operatively linkedto the said relatively displaceable wall part of the closure and theother operatively linked to the remaining part of the closure. Relativerotation between the said threaded shaft and the said nut can beeffected by means of a control knob connected to one of them, thedimensions of the control knob being such as to extend over the saidflexible hinge part of the closure whereby to protect it from incidentultraviolet radiation. This is particularly convenient if the saidflexible hinge is formed as a roll seal as described above since such aseal may comprise relatively thin flexible material which could bedegraded over time by UV radiation causing it to harden and thereforecrack.

In order to achieve a suitable degree of compression of the sealingmaterial, and in particular to allow accommodation of dimensionalvariations (both expansion and contraction) due to thermal dilatation,it is preferred that there be provided means for identifying theattainment of a predetermined energy storage state of the said energystorage means. In embodiments in which the energy storage means comprisea compression spring, the said means for identifying the attainment of apredetermined energy storage state may comprise co-operating componentson two relatively movable members, which come into interferingrelationship with one another when the energy storage means is in thesaid predetermined energy storage state. Preferably the sealing materialcomprises a gel. Suitable gel materials have been described in the priorart, and may comprise one which preferably has a cone penetration valuefrom 100 to 350 (10⁻¹ mm), more preferably 200-260, especially 230-250,and an ultimate elongation of at least 200%. Cone penetration may bechosen to ensure that the material is able to be deformed around theelongate objects to be sealed avoiding air voids, but without excessiveflow or if desired excessive relaxation over time, and the ultimateelongation may be chosen to ensure that on re-entry into the splice casethe material is pulled away from the elongate objects, such asconductors, by the separation of two casing halves of the closure. Conepenetration is measured by ASTM D217-68 at 21° C. on an undisturbedsample using a standard 1:1 scale cone (cone weight 102.5 g, shaftweight 47.5 g), the penetration being measured after 5 seconds.Elongation is measured by ASTM D638-80 at 21° C. using a Type 4 die tocut the sample, and at a speed of 5 cm/minute.

Suitable sealing can be made by gelling curable polyurethane precursormaterials in the presence of substantial quantities of mineral oil, avegetable oil or a plasticizer or a mixture thereof. The amount ofplasticizer may be, for example, 30-70% by weight of the total in thecase of a plasticizer such as trimellitate, or 60-80% in the case of amineral or vegetable oil. Mineral and vegetable oils may be mixed, forexample in the ratio 0.7-2.4 parts by weight of mineral oil to 1 part byweight of vegetable oil. Other suitable sealing materials may be made bycuring reactive silicones with non-reactive, extender, silicones. Afurther class of materials comprises those formed by extending triblockcopolymers, such as styrene-ethylene-butylene-styrene copolymers (forexample that sold under the Shell trade mark Kraton) with a mineral oil.These sealing materials are disclosed in U.S. Pat. Nos. 4,634,207(Debbaut) and 4,716,183 (Gamarra), the disclosures of which areincorporated herein by reference.

Other suitable materials are discussed in detail in InternationalApplication published under WO 92/22114 (Raychem) the disclosure ofwhich is incorporated herein by reference.

It is preferred that the gel is injection moulded into two oppositeparts of the closure although it may be pre-formed as blocks.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be moreparticularly described, by way of example, with reference to theaccompanying drawings in which:

FIG. 1 is a schematic perspective view of a first embodiment of theinvention in assembled condition;

FIG. 2 is a corresponding perspective view of a lower half of theclosure casing of the embodiment of FIG. 1;

FIG. 3 is a sectional view taken on the line III—III of FIG. 2;

FIG. 4 is a sectional view taken on the line IV—IV of FIG. 2;

FIG. 5 is a partial sectional view illustrating the action of the rollseal;

FIG. 6 is a partial sectional view of an alternative embodiment of thepresent invention showing the operation of the inclination means foridentifying a predetermined energy storage state;

FIG. 7 is a perspective view showing the external configuration of anexemplary embodiment of the invention;

FIG. 8 is an exploded perspective view of a further embodiment of theinvention having separate displaceable members in the sealant chamber;and

FIG. 9 is a cutaway perspective view of the embodiment of FIG. 8 in theassembled condition.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Referring now to the drawings, there is shown one part of a closurecasing, generally indicated 11, for housing splices between two cablesonly one of which is schematically represented at 12. The cables may beconductors or optical fibres. It will be appreciated that only one halfof the casing 11 is illustrated, the other half being a mirror image ofsubstantially identical components at the opposite end and have beenomitted for clarity.

As can be seen in FIGS. 1, 2 and 3 the closure casing 11 comprises afirst or tray part 13 and a second or cover part 14 which meet along alongitudinal separation line generally indicated 15 in correspondencewith which there is formed a longitudinal seal which may be ofconventional form and which, therefore, will not be described in detailherein. The two parts 13, 14 of the closure casing 11 define a mainchamber 16 within which splices between the elongate cables 12 may behoused. Appropriate cables organisers, splice connectors and theequipment may be housed in the chamber 16 but are not illustrated herefor clarity. The tray member 13 and cover member 14 have correspondingtransverse partition walls 17, 18 having respective grooves or channels(only one of which, channel 19, is visible in FIG. 2) for receivingrespective crown flanges 20 which define the seatings for receiving thecables 12. Each crown flange 20 is formed as a semi-conical element witha plurality of flexible fingers extending axially from a radial flange21. Such elements are known and described, for example, in our earlierInternational Patent Application PCT/GB95/00469 published underInternational Publication No. WO 95/24756. The radial flange part 21 ofa crown flange is received in the groove 19 to locate it in position,and the difference in diameter between the larger diameter end at theflange 21 and the smaller diameter end at the free end of the flexiblefingers, defines the range of diameters of cable 12 which can beaccommodated.

The end portion of the lower tray part 13, between the partition wall 17and an end wall 22 thereof defines a sealing chamber 23 which is filledwith a gel material 24 in use of the closure casing.

A bottom wall of the sealing chamber 23 comprises a central, slightlydomed, substantially rigid “piston” part 25 having a central boss 26.The piston part 25 is circular in plan form, as can be seen in FIG. 2,and joined to the remainder of the bottom wall 27 of the sealing chamber23 by a generally U-section roll seal 28 comprising a thin, integrallyformed membrane joining the outer periphery of the piston member 25 withthe circular inner perimeter a rigid part of the bottom wall 27 of thesealing chamber 23. As can be seen in FIGS. 3 and 4, the thickness ofthe roll seal membrane 28 is considerably less than that of the bottomwall 27 or the piston part 25 although they are integrally formed of thesame material. Due to the reduced dimensions of the wall thickness theroll seal part 28 is substantially flexible whilst the bottom wall 27and the piston part 25 are substantially rigid.

Through the boss 26 passes a shaft 29 having a threaded end portion andan enlarged head 30 received in a cavity in a central boss 31 of acircular reinforcing disc 32 which has a slightly larger diameter thanthat of the piston part 25 but slightly less than the inner perimeter ofthe bottom wall 27.

The cover part 14 of the casing has a corresponding configuration thecomponents of which are identified with the same reference numerals asthose used for the lower tray part, but distinguished with a ′. Thecover part 14 differs from the tray part 13 only in the configuration ofthe end wall 22′ which in the cover part 14 has a tab 33 for engagementin a correspondingly shaped channel 34.

The shaft 29 passes through the apertured boss 26′ of the “piston”portion 25′ of an upper wall 27′ of the end part of the upper cover 14and is engaged by a nut 35 which is captive in a cavity 36 of a controlknob 37. Between the nut 35 and the “piston” 25′ is a compression coilspring 38.

The gel filling 24 (24′ in the upper part) is preferably injectionmoulded into each half of the closure casing during manufacture. As canbe seen in FIG. 2, in use of the closure casing 11, elongate cables 12are laid into the seatings provided by the crown flanges 20 engaged inthe grooves 19 of the partition wall 17 and a corresponding groove inthe end wall 22. Appropriate splicing operations are performed on theend of the cable 12 projecting into the main chamber 16 to join it, forexample, to corresponding end portions of an aligned cable projectinginto the chamber 16 from the opposite end (not shown) of the casing 11.The cover 14 is then placed over the tray part 13 with suitablelongitudinal seals made along the edges joining at the longitudinaljunction line 15. Such seals are known and will not be described herein.

The gel fillings 24, 24′ which have been introduced into the chamber 23preferably by injection moulding (although pre-shaped blocks mayalternatively although non-preferably be used) meet to form a completefilling for the interior of the chamber 23 and the threaded shaft 29 isthen introduced through the aligned openings in the bosses 26, 26′, thespring 38 is fitted over the end and the control knob 37 fitted byscrewing the nut 35 on to the threaded end of the shaft 29.

The gel material 24 can be placed under a suitable compressive load byturning the knob 37 to compress the spring 38 by an appropriate extent.It is desirable that the spring 38 should not be fully compressed suchthat the adjacent turns thereof come into contact with one another sincethis would not allow relative separation of the movable wall parts (the“pistons” 25, 25′) and to prevent this from happening, whilstnevertheless ensuring that the gel 24 is placed under a suitablecompressive load, an indicator device acting to give the operatorfeedback as to the degree of compression of the spring 38 may beprovided. Such device may, for example, be in the form of twointerfering projections on corresponding relatively movable components,such as that described in International Patent Application publishedunder Publication No. WO 92/22114 the disclosure of which isincorporated herein by reference. A suitable configuration of componentsis described hereinbelow with reference to FIG. 6. This comprisesoppositely directed projections 50, 51 on the control knob 37 and thepiston 25′ which interfere with one another to prevent further rotationof the knob 37 when this and the piston reach a predetermined separationwhich corresponds to a predetermined compression of the spring 38 lessthan full compression.

Alternative arrangements may be made to indicate to the user that asuitable mid-range compression has been achieved, for example byproviding a second spring which comes into play part way through thecompression of the main spring 38, or by a change in the shape of thescrew thread or provision of, for example, a fibre washer all of whichserve to provide an indication to the user by increasing the force whichmust be applied to the control knob 37.

Turning now to FIG. 5 there is shown a schematic illustration of a partof the U-shape section of the roll seal 28′ of the cover part 14. Itwill be appreciated that the roll seal 28′ effectively comprises threeparts namely a radially inner limb 40, a radially outer limb 41 and abight portion 42. In its relaxed state, as formed, the radially innerlimb 40 has its maximum length whilst the radially outer limb 41 has itsminimum length. The bight portion 42 obviously joins these two limbs andis formed from them as the roll seal moves upon displacement of thepiston portion 25′ from the position shown in solid outline in FIG. 5 tothe position shown in broken outline, in which position the radiallyinner and outer limbs 40, 41 are of equal length.

The advantage of providing the roll seal 28′ in the configurationillustrated, namely with its convex face directed towards the interiorof the chamber 23, lies in the fact that, upon displacement of thepiston 25′ from the relaxed position towards a position in which the gel24 is compressed, material of the roll seal 28′ moves radially aroundthe bight portion 42 from the inner limb 40 towards the outer limb 41.Because the inner limb 40 lies at a smaller radius than the outer limb41 the circumference of the radially outer limb portion 41 is greaterthan that of the radially inner limb portion 40 so that the material ofthe roll seal is placed under tension by this movement, which is astress the material is better capable of withstanding than compressivestress which would be the case if the displacement of the piston 25′ tomove from its starting position to its working position resulted intransfer of material from the radially outer limb 41 towards theradially inner limb 40. Although the described configuration ispreferred, it is by no means impossible that an outwardly convex rollseal could be used. Furthermore, although a single U-shape roll seal hasbeen described, it would be possible for this to be a corrugated orbellows-configuration seal with more than one corrugation.

Obviously, as the spring 38 is compressed the shaft 29 is placed undertension drawing together the two pistons 25, 25′ to reduce the volume ofthe sealing chamber 23 and thus place the gel 24 under compression. Thebroken lines 45, 45′ show the maximum excursion of the pistons 25, 25′which can result in a variation in the volume of the sealing chamber 23of a considerable extent, and certainly much more than the change involume which could be achieved using the rigid slidable pistonspreviously known for this purpose. Moreover, the utilisation of anintegrally formed roll seal 28, 28′ provides absolute security againstescape of the gel in these regions, which could not be guaranteed in thecase of a sliding piston.

FIG. 7 shows one proposed configuration for a closure casing of theinvention. In this embodiment the upper and lower halves of the casingare held together by toggle clips 60. This has the advantage of allowingthe closure to be re-enterable to effect changes in the spliceconfiguration or repairs as necessary.

In the alternative embodiment illustrated in FIGS. 8 to 10 there isshown a closure casing, generally indicated 61 comprising twocooperating casing parts 62, 63 in the form of half-shells which can beheld together in juxtaposed relationship by a set of spring clips 64each comprising a closed loop 65 of spring wire and a toggle lever 66having pivot pins 66A which engage in cooperating recesses 68 of theupper (as viewed in the drawings) casing half 62 whereby to clamp thetwo casing halves together.

The lower (as viewed in the drawings) casing half 63 is shown in FIG. 8with a portion adjacent its end cut away to illustrate the internalconfiguration of the sealing means at the end.

A transverse end wall 67 has two arcuate, semi-circular notches 68, 69which, together with corresponding notches 70, 71 in an end wall 72 ofthe “upper” casing half 62 form circular openings (only one of which,identified 73, is visible in FIG. 9) through which passes an elongatearticle 74, in this example a bundle of optical fibres or cablesintended to be spliced or joined within the casing 61.

A second transverse wall 75 parallel to the transverse end wall 67defines, with this latter, a chamber 77 for receiving a clamp member 78loosely fitted within the chamber 77 and to be described in more detailbelow. A second transverse wall 76 closely adjacent the wall 75 definesa narrow slot 79 for receiving a lip 80 of a crown flange 81, whereby tolocate the crown flange in position over a lower plunger 82 having twoshaped channels 83, 84 for receiving respective parts of the crownflange 81.

The plunger 82 is located between the transverse wall 76 and a furtherwall (not visible in the drawings) which between them define a sealantchamber 85 which will be described in more detail below.

Projecting upwardly from a central portion of the plunger 82 is acylindrical sleeve 86 which, as can be seen in FIG. 9, carries a helicalinternal rib forming a thread 87 for cooperation with a threaded part 88of a stem 89 at the upper end of which is located an operating knob 90.The rod 89 is located within a sleeve 91 of an upper plunger 92 a skirtportion of which engages over the cylindrical sleeve 86 when the casing61 is assembled. The lower plunger 82 and upper plunger 92 defineopposite facing walls of the sealant chamber 85 and can be caused toapproach or separate from one another by manipulation of the knob 90causing the shaft 89 to rotate thereby screwing the threaded portion 88into or out from engagement with the thread 87 in the lower plunger 82.

Like the lower plunger 82 the upper plunger 92 has shaped channels 93for receiving cooperating crown flanges 94.

As can be seen in FIG. 9, a smaller-diameter elongate article 95 isshown engaged between the crown flanges 81, 94 at the relatively narrowtapered end which engages over the article 95. Gel sealant of a typedescribed hereinbefore may be introduced into the sealant chamber 85,either by injection moulding as described above, or by the introductionof separate gel elements. Upon introduction of the elongate articles 74,95 and assembly of the casing 61, a secure seal against the ingress ofenvironmental contaminants into the interior of the casing can beachieved by turning the knob 90 to cause the plungers 82 and 92 toapproach one another, maintaining a symmetrical configuration within thechamber 85, and applying a compressive force to the gel.

A coil spring 96 is engaged over the threaded shaft 88 between the knob90 and the upper face of the plunger 92, with a bearing plate 97interposed between them, such that the force between the shaft 89 andthe plunger 92 is transmitted via the spring 96 which is compressed asthe shaft 89 is screwed into the plunger 82 thereby creating a residualenergy store which maintains the compression on the gel in the mannerdescribed hereinabove in relationship to the embodiment of FIGS. 1 to 8.A suitable arrangement for determining when an appropriate degree ofcompression of the spring 96 has been achieved may also be provided asdescribed hereinbefore, although such arrangement is not illustrated inFIGS. 9 to 10. The foregoing is illustrative of the present inventionand is not to be construed as limiting thereof. Although a few exemplaryembodiments of this invention have been described, those skilled in theart will readily appreciate that many modifications are possible in theexemplary embodiments without materially departing from the novelteachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention as defined in the claims. In the claims, means-plus-functionclauses are intended to cover the structures described herein asperforming the recited function and not only structural equivalents butalso equivalent structures. Therefore, it is to be understood that theforegoing is illustrative of the present invention and is not to beconstrued as limited to the specific embodiments disclosed, and thatmodifications to the disclosed embodiments, as well as otherembodiments, are intended to be included within the scope of theappended claims. The invention is defined by the following claims, withequivalents of the claims to be included therein.

What is claimed is:
 1. A closure casing for enclosing an elongatearticle, the closure casing comprising: two opposite casing parts havingholding means for holding them together in juxtaposed relationship, eachcasing part having respective cavities which together form a sealantchamber for receiving sealant material through which the elongatearticle passes in penetrating the closure casing; compression means forapplying a compressive force to the sealant material transversely of thelength of the elongate article to urge the sealant into contact with theelongate article to seal thereto; wherein the compression means furthercomprises a displaceable element guided for movement within the sealantchamber in a direction substantially transverse the length of theelongate article; and wherein the displaceable element further comprisesat least one plunger guided by externally operable screw threadedposition-adjustment means rotatably engaging the at least one plunger.2. A closure casing according to claim 1, in which the at least oneplunger comprises two relatively displaceable plungers interconnectedand guided for substantially rectilinear movement within the sealantchamber.
 3. A closure casing according to claim 2, in which the twoplungers are interconnected by the position-adjustment means.
 4. Aclosure casing according to claim 1 further comprising energy storagemeans positioned between the position-adjustment means and the at leastone plunger.
 5. A closure casing according to claim 4, in which theenergy storage means further comprises a spring.
 6. A closure casingaccording to claim 5, in which the spring comprises a compression coilspring.
 7. A closure casing according to claim 4 wherein theposition-adjustment means further comprises a threaded shaft havingoperating means at one end thereof by which the threaded shaft isturnable, and a cooperating threaded hole in, the at least one plunger,the energy storage means acting between an additional plunger and theoperating means.
 8. A closure casing according to claim 7, in which theoperating means comprises at least one of a manually operable knob or ahandle.
 9. A closure casing according to claim 8, in which theidentifying means further comprises co-operating components on tworelatively movable members, which members come into an interferingrelationship with one another when the energy storage means is in thepredetermined energy storage state.
 10. A closure casing according toclaim 4 further comprising identifying means for identifying attainmentof a predetermined energy storage state of the energy storage means. 11.A closure casing according to claim 1 wherein the sealing materialcomprises at least one of a gel or gelloid.
 12. A closure casingaccording to claim 11 wherein the sealing material is injection mouldedinto the closure casing.
 13. A closure casing comprising: a casing parthaving at least one opening configured to receive an elongate objectwithin the casing part; a sealing chamber defined by the casing partpositioned adjacent the at least one opening so as to receive theelongate object in the sealing chamber; a sealant material positioned inthe sealing chamber; a relatively displaceable wall part of the casingpart communicatively contacting the sealant material; a flexible hingepart coupling the relatively displaceable wall part to another part ofthe casing part so as to allow movement of the relatively displaceablewall part relative to the another part of the casing part; and aposition-adjustment shaft positioned to displace the relativelydisplaceable wall part so as to adjust a volume of the sealant chamber.14. A closure casing according to claim 13 wherein the flexible hingepart comprises at least one of a corrugated part, a bellows part or arolling seal.
 15. A closure casing according to claim 14 wherein theflexible hinge part comprises a U-section rolling seal.
 16. A closurecasing according to claim 15 wherein the U-section rolling sealcomprises an integrally formed membrane joining the relativelydisplaceable wall part and the another part of the casing, the membranebeing thinner than the relatively displaceable wall part and the anotherpart of the casing.
 17. A closure casing according to claim 15 whereinthe U-section rolling seal is convex towards the sealing chamber.
 18. Aclosure according to claim 14 wherein the relatively displaceable wallpart comprises a domed piston part and wherein the flexible hinge partconnects an outer periphery of the domed piston part to the another partof the casing.
 19. A closure according to claim 18 wherein the anotherpart of the casing comprises a rigid portion of a wall of the sealingchamber, the rigid portion having an inner perimeter defining asubstantially circular opening in the sealing chamber, the domed pistonpart being positioned in the circular opening and the flexible hingepart connecting the outer periphery of the domed piston part to theinner perimeter of the rigid portion.
 20. A closure according to claim14 wherein the casing part comprises a first part and a mating secondpart and a seal between the first part and the second part.
 21. Aclosure according to claim 20 further comprising a second relativelydisplaceable wall part of the casing part positioned across the sealingchamber from the first relatively displaceable wall part, wherein thefirst relatively displaceable wall part is coupled to the first part bythe flexible hinge part and the second relatively displaceable wall partis coupled to the second part by a second flexible hinge part.
 22. Aclosure according to claim 21 wherein the position-adjustment shaftdisplaces both the first relatively displaceable wall part and thesecond relatively displaceable wall part so as to provide a symmetricalconfiguration within the sealing chamber when the relativelydisplaceable wall parts are displaced towards each other to reduce thevolume of the sealant.
 23. A closure according to claim 22 furthercomprising a spring that couples the position-adjustment shaft to atleast one of the relatively displaceable wall parts, the spring beingpositioned to provide a compressive load on the sealing material throughthe at least one of the relatively displaceable wall parts.
 24. Aclosure according to claim 23 further comprising identifying means foridentifying attainment of a predetermined compression of the spring. 25.A closure according to claim 14 wherein the flexible hinge part providesa seal between the relatively displaceable wall part and the anotherpart of the casing part so as to provide security against escape of thesealant material from the sealing chamber between the relativelydisplaceable wall part and the another part of the casing part.
 26. Aclosure casing comprising: a casing part having at least one openingconfigured to receive an elongate object within the casing part; asealing chamber defined by the casing part positioned adjacent the atleast one opening so as to receive the elongate object in the sealingchamber; a sealant material positioned in the sealing chamber; arelatively displaceable wall part of the casing part communicativelycontacting the sealant material; a flexible hinge part coupling therelatively displaceable wall part to another part of the casing part soas to allow movement of the relatively displaceable wall part relativeto the another part of the casing part; and a compression means forapplying a compressive force to the sealant material through therelatively displaceable wall part.
 27. A closure casing comprising: acasing part having at least one opening configured to receive anelongate object within the casing part; a sealing chamber defined by thecasing part positioned adjacent the at least one opening so as toreceive the elongate object in the sealing chamber; a sealant materialpositioned in the sealing chamber; a displaceable plunger defining awall of the sealing chamber; and an externally operable shaft threadablyengaging the plunger so as to displace the plunger to adjust a volume ofthe sealant chamber.
 28. A closure casing according to claim 27 whereinthe plunger further comprises a sleeve member projecting upwardly from acentral portion of the plunger, the central portion including a helicalinternal rib forming a thread, the externally operable shaft engagingthe thread.
 29. A closure casing according to claim 28 furthercomprising a second displaceable plunger defining a wall of the sealingchamber opposite the first displaceable plunger, wherein the externallyoperable shaft further engages the second plunger so as to displace thesecond plunger to adjust a volume of the sealant chamber.
 30. A closurecasing according to claim 29 further comprising a spring coupling theexternally operable shaft to the second plunger.
 31. A closure accordingto claim 30 further comprising identifying means for identifyingattainment of a predetermined compression of the spring.
 32. A closurecasing according to claim 29 wherein the second plunger includes asleeve member extending from a central portion of the second plungertowards the first plunger, the sleeve member of the second plunger beingconfigured to slidably engage the sleeve member of the first plungerwhen the first plunger is displaced towards the second plunger.